What is CVE-2021-21491?

CVE-2021-21491 is a medium-severity vulnerability in SAP Netweaver Application Server Java, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 6.1/10. Published 2021-03-10.

How severe is CVE-2021-21491?

Medium severity. CVSS v3 base score is 6.1 out of 10.

Open Redirect in SAP Netweaver Application Server Java

CVE-2021-21491

SAP Netweaver Application Server Java (Applications based on WebDynpro Java) versions 7.00, 7.10, 7.11, 7.20, 7.30, 7.31, 7.40, 7.50, allow an attacker to redirect users to a malicious site due to Reverse Tabnabbing vulnerabilities.

Vulnerability class: Open Redirect

Published 2021-03-10 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.007 (51.0th percentile), scored 2026-10-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 51st percentile — 51.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: +0.000

Affected products

SAP Netweaver Application Server Java — versions 7.00, 7.10, 7.11
SAP Se Netweaver Application Server Java (Applications Based On Web Dynpro Java) — versions < 7.00, < 7.10, < 7.11

Weakness classification (CWE)

CWE-601 — URL Redirection to Untrusted Site (Open Redirect)

References

wiki.scn.sap.com/wiki/pages/viewpage.action (Vendor Advisory)
launchpad.support.sap.com/ (Permissions Required, Vendor Advisory)

Frequently asked questions

What is CVE-2021-21491?: CVE-2021-21491 is a medium-severity vulnerability in SAP Netweaver Application Server Java, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 6.1/10. Published 2021-03-10.
How severe is CVE-2021-21491?: Medium severity. CVSS v3 base score is 6.1 out of 10.